Bone infarcts

This is a 52 year old male who presents with knee and ankle pain. Frontal and lateral radiographs of the knee demonstrate intramedullary calcified lesions with a serpiginous pattern in the distal femur and proximal tibia. The appearance of the lesions in the femur and tibia has been described as having a "bone-within-bone" appearance. The radiographic appearance of the lesions by themselves can be seen with bone infarcts or enchondromas. The multifocality of these lesions is most consistent with bone infarcts. This patient was diagnosed with sickle cell disease as a teenager, a disease which commonly results in multifocal bone infarcts. Bone infarcts are associated with pain, and should not be mistaken for a malignant bone tumor.